The Hollister Property is located at the intersection of the Carlin Trend and the Northern Nevada Rift. The Carlin trend is a northwest trending, 50-mile long metallogenic corridor, which hosts significant opencast and underground operations that have produced in excess of 70 million ounces of gold. Carlin Trend-type mineralization is 38-43 Myrs (Eocene) in age. The Northern Nevada Rift is a north - northwest trending structural feature made up of bimodal volcanic rocks that host Miocene-aged (13-15 Myr) low sulphur-type epithermal gold deposits such as Midas, Mule Canyon, Buckskin National and Hollister. The Paleozoic stratigraphy and Eocene magmatic pulse that is critical to the development of Carlin-type deposits to the southwest are in evidence at Hollister, as are the Miocene mineralizing events. The Hollister stratigraphic section includes Ordovician sedimentary rocks intruded by mid-Eocene plutons and unconformably overlain by a veneer of Miocene volcanic and volcano-sedimentary rocks. Devonian sedimentary rocks have been intersected at a depth below the Ordovician sediments under the Roberts Mountain Thrust.
Epithermal gold mineralization at the Hollister Property occurred in the early Miocene (15.1 Myr) and is directly related to right - lateral wrench tectonics associated with the Northern Nevada Rift, where it over-prints the Carlin Trend. The Hollister Property hosts a low-sulfidation Au-Ag epithermal system characterized by banded quartz veins with electrum, native gold and silver selenides. To date over 40 mineralized veins have been modeled in the main Clementine-Gwenivere vein systems. The veins are narrow (1-3 feet wide), and commonly display colliform banding, brecciation and silicification features indicative of multiple pulses of fluid movement. The low-sulphur epithermal vein systems form as part of a geothermal system around the interface of hot volcanic derived hydrothermal fluids and cold meteoric water influx. Similar active systems such as Yellowstone National Park (Wyoming) and the Taupo Volcanic Zone (New Zealand) demonstrate many of the features observed at Hollister.
Although mineral resources and reserves are delineated on the epithermal vein system hosted in Ordovician metasedimentary host rocks, continued exploration of the orebody has delineated zones of disseminated gold mineralization in the overlying Tertiary volcanic, within which restricted structures host zones up to 100 oz per ton Au. These super high grade Blanket Zones are being accessed and developed as a separate ore source, and have to date have been tested metallurgically at a separate whole ore roasting facility.
Some of the primary geological elements of the sediment-hosted gold deposits of the Carlin Trend are present at the Hollister Property, including Eocene intrusive rocks and lower-plate carbonate rocks. The Hatter stock (a grandioritic intrusive) at the Hollister Property has been dated at 39 Ma and is similar to 39 Ma biotite-feldspar porphyry dikes occurring in the Goldstrike area 5 miles SE in the Carlin trend. The main pulse of gold mineralization on the Carlin Trend is dated at about 38 Ma and commonly thought to be associated with late-Eocene magmatism.